Analitical approximation of $<\phi^2>$ for a massive scalar field in static spherically symmetric spacetimes

An analitical approximation of $<\phi^2>$ for a massive scalar field in a zero temperature vacuum state in static spherically symmetric spacetimes is obtained. The calculations are based on the method for computing vacuum expectations values for scalar fields in general static spherically symmetric spacetimes derived by Anderson, Hiscock and Samuel [Phys. Rev. D {\bf 51}, 4337 (1995)]. The analitical approximation is used to compute $<\phi^2>$ in Schwarzschild and wormhole spacetimes.